SAGE Computing Services
Customised Oracle Training Workshops and Consulting
Creative Conditional Compilation
… and “raisin...
The example everybody’s seen…
FUNCTION qty_booked(p_resource IN VARCHAR2
,p_date IN DATE)
RETURN NUMBER
$IF dbms_db_versio...
The example everybody’s seen…
FUNCTION qty_booked(p_resource IN VARCHAR2FUNCTION qty_booked(p_resource IN VARCHAR2
,p_date...
• PL/SQL User’s Guide & Reference
10g Release 2
– Fundamentals of the PL/SQL Language
• Conditional Compilation
Availability
• 11g
• 10g Release 2
– Enabled out of the box
• 10.1.0.4 – Once patched, enabled by default
– Disable using ...
Catch 22
INDICES OF
Catch 22
Conditional
Compilation
Patch
INDICES OF
Facilitates removal of unnecessary code at compile time
Performance
Readability
Accuracy Testing
It's cool!
Selection Directives
$IF boolean_static_expression $THEN text
[ $ELSIF boolean_static_expression $THEN text ]
[ $ELSE text...
First demo
cc1a
cc1b
cc1c
cc1d
Inquiry Directives
<< anon >>
BEGIN
DBMS_OUTPUT.PUT_LINE('Unit:'||$$PLSQL_UNIT);
DBMS_OUTPUT.PUT_LINE('Line:'||$$PLSQL_LINE);
END anon;
/
Uni...
> CREATE OR REPLACE PROCEDURE sw_test IS
BEGIN
DBMS_OUTPUT.PUT_LINE('Unit:'||$$PLSQL_UNIT);
DBMS_OUTPUT.PUT_LINE('Line:'||...
ALTER SESSION SET PLSQL_CCFLAGS = 'max_sentence:100';
Session altered.
> BEGIN
IF p_sentence > $$max_sentence THEN
DBMS_OUTPUT.PUT_LINE('Parole Available');
ELSE
DBMS_OUTPUT.PUT_LINE('Life');
E...
ALTER SYSTEM SET PLSQL_CCFLAGS =
'VARCHAR2_SIZE:100, DEF_APP_ERR:-20001';
DECLARE
lc_variable_chr VARCHAR2($$VARCHAR2_SIZE...
Reuse Settings
ALTER SESSION SET PLSQL_CCFLAGS = 'MY_PI:314';
CREATE OR REPLACE PROCEDURE universe_alpha IS
BEGIN
DBMS_OUTPUT.PUT_LINE('A...
Some actual examples?
Using new version code today
$IF dbms_db_version.ver_le_10 $THEN
-- version 10 and earlier code
$ELSIF dbms_db_version.ver...
10.1 vs 10.2 dbms_output
CREATE OR REPLACE PROCEDURE sw_debug (p_text IN
VARCHAR2) IS
$IF $$sw_debug_on $THEN
l_text VARCHAR2(32767);
$END
BEGIN
$I...
CREATE OR REPLACE PROCEDURE sw_debug (p_text INCREATE OR REPLACE PROCEDURE sw_debug (p_text IN
VARCHAR2) ISVARCHAR2) IS
$I...
CREATE OR REPLACE PROCEDURE sw_debug (p_text INCREATE OR REPLACE PROCEDURE sw_debug (p_text IN
VARCHAR2) ISVARCHAR2) IS
$I...
10g vs 11g result_cache
FUNCTION quantity_ordered
(p_item_id IN items.item_id%TYPE)
RETURN NUMBER
$IF dbms_version.ver_le_...
9i vs 10g Bulk Insert
CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS
PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS
BEGIN
$IF dbms_db_version.ver...
CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS
PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS
BEGIN
$IF dbms_db_version.ver...
CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS
PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS
BEGIN
$IF dbms_db_version.ver...
Paradigm Examples
Latent debugging code
CREATE OR REPLACE PACKAGE pkg_debug IS
debug_flag CONSTANT BOOLEAN := FALSE;
END pkg_debug;
/
CREATE OR REPLACE PROCEDURE ...
Assertions
“Assertions should be used to document
logically impossible situations —
Development tool
Testing Aid
In-line Documentatio...
Latent Assertions
“The removal of assertions from production code is
almost always done automatically.
It usually is done via conditional co...
$IF $$asserting
OR CC_assertion.asserting
$THEN
IF p_param != c_pi*r*r THEN
raise_application_error(..
END IF;
$END
-- ind...
Testing subprograms only in package body
CREATE PACKAGE universe IS
PROCEDURE create_sun;
PROCEDURE create_planets;
-- CC test procedure
PROCEDURE test_orbit;
END ...
CREATE PACKAGE universe IS
PROCEDURE create_sun;
PROCEDURE create_planets;
-- CC test sequence
PROCEDURE test_run;
END uni...
Mock objects
FUNCTION get_emp(p_emp_id IN emp.emp_id%TYPE)
RETURN t_emp IS
l_emp t_emp;
BEGIN
$IF $$mock_emp $THEN
l_emp.emp_name := 'S...
Comparing competing implementations
during prototyping
PROCEDURE xyz IS
$IF $$alternative = 1 $THEN
-- varray declaration
$$ELSIF $$alternative = 2 $THEN
-- nested table declara...
Component Based Installation
PACKAGE BODY core IS
PROCEDURE execute_component(p_choice IN VARCHAR2) IS
BEGIN
CASE p_choice -- Base is always installed....
Get It Right with the Error Directive
$IF $$PLSQL_OPTIMIZE_LEVEL != 2
$THEN
$ERROR 'intensive_program must be compiled with
maximum optimisation'
$END
$END
BEGIN
...
/*
*
* Note to self: Must remember to finish this bit
*
*/
...
END;
BEGIN
...
-- Jacko: this doesn’t work, fix before moving to prod!
...
END;
1 CREATE PROCEDURE process_court_outcome IS
2 BEGIN
3 IF lr_victim.age > 18 THEN
4 send_to_prison(lr_victim);
5 ELSE
6 $ER...
Post-processed Source
Demo: cc2
Smaller, Faster Run-Time Code Is in Your Future
Good Practices
Inquiry directives have null values for normal behaviour
$IF $$cc_flag = 'x' $THEN
cc_code;
$END
Choose restriction type carefully
$IF $$debug_on
OR module_y.cc_debug
$THEN
sw_debug('Error');
$END
but there’s always this...
SQL> define debug=/*
begin
&debug
select 'conditionally'
from dual;
-- */
select 'always'
from dual;
end;
/
SAGE Computing Services
Customised Oracle Training Workshops and Consulting
Questions and Answers?
Presentations are avail...
Oracle PL/SQL - Creative Conditional Compilation
Upcoming SlideShare
Loading in …5
×

Oracle PL/SQL - Creative Conditional Compilation

913
-1

Published on

Abstract: Oracle released a feature in 10g Release 2 they thought worthy of facilitating in previous versions via patch sets - so I thought it was worthy enough for a closer look.

Conditional compilation isn't a foreign concept in the programming world, and for the developer aficionado it's a wonderful paradigm to explore.

Conditional compilation was designed with the main intention of being able to create database version specific code. With the recent advent of 11g, developers can actually start adding 11g features to their 10g code today!

However it provides the savvy PL/SQL developer to enhance their code in more ways than just gearing up for the next release… Dust of your software engineering hats and discover how to utilise conditional compilation to explore concepts such as latent self tracing code; latent assertions; and enhanced prototyping for your unit tests.

This seminar will illustrate several examples of conditional compilation that will open your mind; ultimately benefit your users; and can be implemented as far back as 9.2!

Published in: Data & Analytics, Technology
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
913
On Slideshare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
21
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide
  • Some powerpoint pezzaz straight off the bat, let’s get into an example you’ve probably seen before so you all know what I’m talking about
  • And one that Penny even details later in the conference. I’m going to talk in depth about the concept behind conditional compilation and delve into a few more uses for you.
  • This funky bit of code here is the concept where going to talk about. As usual, I’ll fly through the semantics because that’s all available in the doco
  • You don’t need to look far to find it.
    What I really want to concentrate on with you is more diverse applications of this concept, using programming principles that have been around for a while.
  • Feature of 10gr2, but made available to previous releases via patchsets.
    Historians of Oracle Database might be interested to know that the introduction
    of PL/SQL conditional compilation was motivated by a request from Oracle’s
    Applications Division for a solution to the problem of code spanning multiple releases.
  • Catch22 - So you must patch your previous db to make conditional compilation available to prepare for new release
  • Catch22 - So you must patch your previous db to make conditional compilation available to prepare for new release
  • I&amp;apos;ll basically go through all of these points in the seminar
  • Note the lack of semicolon, end ‘if’;
  • This demo really needs to highlight the difference between enquiry directive usage. Diff between $$x and static constant. Usage behind both examples can differ depending on what you are trying to accomplish. Example shown later in competing soln.
  • Designers should choose carefully with their names,
    to minimise collision
    Accidental discovery
    Reserved words
  • Even more valuable, I can use inquiry directives in places in my code where a variable is not allowed. Here are two examples
    Also note it’s system or session specific
  • A quick word for developers to ensure the same compiler directives are used when functions recompiled later
  • Let’s have a quick look at was this feature was made for
  • A quick word for developers to ensure the same compiler directives are used when functions recompiled later
  • Don’t forget the whole poor software engineering premise to this funky technology though -
    never recommend putting untested code in production.
    When you upgrade to 11g obviously you’d test the upgrade in a non-production environment as
    part of search for side effects or compilation issues.
    Just means you haven’t forgotten this new feature. We won’t flick switch to 11g on prod anyway.
  • OK, you don&amp;apos;t upgrade often. How about these paradigms
  • We saw this one in the demo…
  • Ok, who’se heard of assertions?
  • Ok, who’se heard of LATENT assertions?
  • “In tests, a mock object behaves exactly like a real object with one crucial
    difference: the programmer will hard-code return values for its methods...”
  • REALLY basic example here, the white paper example I saw was on it&amp;apos;s way
    towards some sophisticated testing, but there is so much potential here.
    for embedding test plans, particular for subprograms in packages
  • Highlight not so much the code, but the concept behind this. Making sure code doesn’t get lost, competing examples don’t get lost and confused as commented code. Life may only be days/weeks, not production code. But the concept does lead on to the idea of component based installation for licensed software.
  • Inquiry directives allow quite flexible playing around with other triggers or events elsewhere in your app that you can control your testing with.
  • Much of a segue from the previous solution, but too deep a topic to go to any more detail today than a quick conceptual example
  • Pick up any textbook that talks about conditional compilation.
  • If all else fails
  • Thanks Connor
  • Oracle PL/SQL - Creative Conditional Compilation

    1. 1. SAGE Computing Services Customised Oracle Training Workshops and Consulting Creative Conditional Compilation … and “raising the bar” with yourPL/SQL Sco tt We sle y Systems Consultant
    2. 2. The example everybody’s seen… FUNCTION qty_booked(p_resource IN VARCHAR2 ,p_date IN DATE) RETURN NUMBER $IF dbms_db_version.ver_le_10 $THEN $ELSE RESULT_CACHE $END IS li_total PLS_INTEGER := 0; BEGIN SELECT SUM(b.qty) INTO li_total FROM bookings b, events e WHERE p_date BETWEEN e.start_date AND e.end_date AND b.resource = p_resource; RETURN li_total END qty_booked;
    3. 3. The example everybody’s seen… FUNCTION qty_booked(p_resource IN VARCHAR2FUNCTION qty_booked(p_resource IN VARCHAR2 ,p_date IN DATE),p_date IN DATE) RETURN NUMBERRETURN NUMBER $IF dbms_db_version.ver_le_10 $THEN $ELSE RESULT_CACHE $END ISIS li_total PLS_INTEGER := 0;li_total PLS_INTEGER := 0; BEGINBEGIN SELECT SUM(b.qty)SELECT SUM(b.qty) INTO li_totalINTO li_total FROM bookings b, events eFROM bookings b, events e WHERE p_date BETWEEN e.start_date AND e.end_dateWHERE p_date BETWEEN e.start_date AND e.end_date AND b.resource = p_resource;AND b.resource = p_resource; RETURN li_totalRETURN li_total END qty_booked;END qty_booked;
    4. 4. • PL/SQL User’s Guide & Reference 10g Release 2 – Fundamentals of the PL/SQL Language • Conditional Compilation
    5. 5. Availability • 11g • 10g Release 2 – Enabled out of the box • 10.1.0.4 – Once patched, enabled by default – Disable using “_parameter” • 9.2.0.6 – Once patched, disabled by default – Enable using “_parameter”
    6. 6. Catch 22 INDICES OF
    7. 7. Catch 22 Conditional Compilation Patch INDICES OF
    8. 8. Facilitates removal of unnecessary code at compile time Performance Readability Accuracy Testing It's cool!
    9. 9. Selection Directives $IF boolean_static_expression $THEN text [ $ELSIF boolean_static_expression $THEN text ] [ $ELSE text ] $END Inquiry Directives DBMS_OUTPUT.PUT_LINE($$PLSQL_LINE); ALTER SESSION SET PLSQL_CCFLAGS='max_sentence:100'; IF sentence > $$max_sentence THEN Error Directives $IF $$PLSQL_OPTIMIZE_LEVEL != 2 $THEN $ERROR 'intensive_program must be compiled with maximum optimisation' $END $END Semantics
    10. 10. First demo cc1a cc1b cc1c cc1d
    11. 11. Inquiry Directives
    12. 12. << anon >> BEGIN DBMS_OUTPUT.PUT_LINE('Unit:'||$$PLSQL_UNIT); DBMS_OUTPUT.PUT_LINE('Line:'||$$PLSQL_LINE); END anon; / Unit: Line:4
    13. 13. > CREATE OR REPLACE PROCEDURE sw_test IS BEGIN DBMS_OUTPUT.PUT_LINE('Unit:'||$$PLSQL_UNIT); DBMS_OUTPUT.PUT_LINE('Line:'||$$PLSQL_LINE); END sw_test; / Procedure created. > exec sw_test Unit:SW_TEST Line:4
    14. 14. ALTER SESSION SET PLSQL_CCFLAGS = 'max_sentence:100'; Session altered.
    15. 15. > BEGIN IF p_sentence > $$max_sentence THEN DBMS_OUTPUT.PUT_LINE('Parole Available'); ELSE DBMS_OUTPUT.PUT_LINE('Life'); END IF; END; / Life
    16. 16. ALTER SYSTEM SET PLSQL_CCFLAGS = 'VARCHAR2_SIZE:100, DEF_APP_ERR:-20001'; DECLARE lc_variable_chr VARCHAR2($$VARCHAR2_SIZE); e_def_app_err EXCEPTION; PRAGMA EXCEPTION_INIT (e_def_app_err, $$DEF_APP_ERR); BEGIN --> rest of your code END anon; /
    17. 17. Reuse Settings
    18. 18. ALTER SESSION SET PLSQL_CCFLAGS = 'MY_PI:314'; CREATE OR REPLACE PROCEDURE universe_alpha IS BEGIN DBMS_OUTPUT.PUT_LINE('Alpha pi = '||$$my_pi/100); END; CREATE OR REPLACE PROCEDURE universe_gamma IS BEGIN DBMS_OUTPUT.PUT_LINE('Gamma pi = '||$$my_pi/100); END; CREATE OR REPLACE PROCEDURE universe_oz IS BEGIN DBMS_OUTPUT.PUT_LINE('Oz pi = '||$$my_pi/100); END;ALTER PROCEDURE universe_alpha COMPILE PLSQL_CCFLAGS = 'MY_PI:289' REUSE SETTINGS; ALTER PROCEDURE universe_gamma COMPILE PLSQL_CCFLAGS = 'MY_PI:423' REUSE SETTINGS; > BEGIN universe_alpha; universe_gamma; universe_oz; END; / Alpha pi = 2.89 Gamma pi = 4.23 Oz pi = 3.14
    19. 19. Some actual examples?
    20. 20. Using new version code today $IF dbms_db_version.ver_le_10 $THEN -- version 10 and earlier code $ELSIF dbms_db_version.ver_le_11 $THEN -- version 11 code $ELSE -- version 12 and later code $END
    21. 21. 10.1 vs 10.2 dbms_output
    22. 22. CREATE OR REPLACE PROCEDURE sw_debug (p_text IN VARCHAR2) IS $IF $$sw_debug_on $THEN l_text VARCHAR2(32767); $END BEGIN $IF $$sw_debug_on $THEN -- Let’s provide debugging info $IF dbms_db_version.ver_le_10_1 $THEN -- We have to truncate for <= 10.1 l_text := SUBSTR(p_text, 1 ,200); $ELSE l_text := p_text; $END DBMS_OUTPUT.PUT_LINE(p_text); $ELSE -- No debugging NULL; $END END sw_debug;
    23. 23. CREATE OR REPLACE PROCEDURE sw_debug (p_text INCREATE OR REPLACE PROCEDURE sw_debug (p_text IN VARCHAR2) ISVARCHAR2) IS $IF $$sw_debug_on $THEN l_text VARCHAR2(32767); $END BEGINBEGIN $IF $$sw_debug_on $THEN -- Let’s provide debugging info $IF dbms_db_version.ver_le_10_1 $THEN -- We have to truncate for <= 10.1 l_text := SUBSTR(p_text, 1 ,200); $ELSE l_text := p_text; $END DBMS_OUTPUT.PUT_LINE(p_text); $ELSE$ELSE -- No debugging-- No debugging NULL;NULL; $END$END END sw_debug;END sw_debug;
    24. 24. CREATE OR REPLACE PROCEDURE sw_debug (p_text INCREATE OR REPLACE PROCEDURE sw_debug (p_text IN VARCHAR2) ISVARCHAR2) IS $IF $$sw_debug_on $THEN$IF $$sw_debug_on $THEN l_text VARCHAR2(32767);l_text VARCHAR2(32767); $END$END BEGINBEGIN $IF $$sw_debug_on $THEN$IF $$sw_debug_on $THEN -- Let’s provide debugging info-- Let’s provide debugging info $IF dbms_db_version.ver_le_10_1 $THEN -- We have to truncate for <= 10.1 l_text := SUBSTR(p_text, 1 ,255); $ELSE$ELSE l_text := p_text;l_text := p_text; $END$END DBMS_OUTPUT.PUT_LINE(p_text);DBMS_OUTPUT.PUT_LINE(p_text); $ELSE$ELSE -- No debugging-- No debugging NULL;NULL; $END$END END sw_debug;END sw_debug;
    25. 25. 10g vs 11g result_cache FUNCTION quantity_ordered (p_item_id IN items.item_id%TYPE) RETURN NUMBER $IF dbms_version.ver_le_10 $THEN -- nothing $ELSE RESULT_CACHE $END IS BEGIN ...
    26. 26. 9i vs 10g Bulk Insert
    27. 27. CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS BEGIN $IF dbms_db_version.ver_le_9 $THEN DECLARE l_dense t_sw_tab; ln_index PLS_INTEGER := sw_tab.FIRST; BEGIN << dense_loop >> WHILE (l_index IS NOT NULL) LOOP l_dense(l_dense.COUNT + 1) := sw_tab(l_index); l_index := sw_tab.NEXT(l_index); END LOOP dense_loop; FORALL i IN 1..l_dense.COUNT INSERT INTO sw_table VALUES l_dense(i); END; $ELSE FORALL i IN INDICES OF sw_tab INSERT INTO sw_table VALUES sw_tab(i); $END END sw_insert; END sw_bulk_insert;
    28. 28. CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS BEGIN $IF dbms_db_version.ver_le_9 $THEN DECLARE l_dense t_sw_tab; ln_index PLS_INTEGER := sw_tab.FIRST; BEGIN << dense_loop >> WHILE (l_index IS NOT NULL) LOOP l_dense(l_dense.COUNT + 1) := sw_tab(l_index); l_index := sw_tab.NEXT(l_index); END LOOP dense_loop; FORALL i IN 1..l_dense.COUNT INSERT INTO sw_table VALUES l_dense(i); END; $ELSE$ELSE FORALL i IN INDICES OF sw_tabFORALL i IN INDICES OF sw_tab INSERT INTO sw_tableINSERT INTO sw_table VALUES sw_tab(i);VALUES sw_tab(i); $END$END END sw_insert; END sw_bulk_insert;
    29. 29. CREATE OR REPLACE PACKAGE BODY sw_bulk_insert IS PROCEDURE sw_insert (sw_tab IN t_sw_tab) IS BEGIN $IF dbms_db_version.ver_le_9 $THEN$IF dbms_db_version.ver_le_9 $THEN DECLAREDECLARE l_dense t_sw_tab;l_dense t_sw_tab; ln_index PLS_INTEGER := sw_tab.FIRST;ln_index PLS_INTEGER := sw_tab.FIRST; BEGINBEGIN << dense_loop >><< dense_loop >> WHILE (l_index IS NOT NULL) LOOPWHILE (l_index IS NOT NULL) LOOP l_dense(l_dense.COUNT + 1) := sw_tab(l_index);l_dense(l_dense.COUNT + 1) := sw_tab(l_index); l_index := sw_tab.NEXT(l_index);l_index := sw_tab.NEXT(l_index); END LOOP dense_loop;END LOOP dense_loop; FORALL i IN 1..l_dense.COUNTFORALL i IN 1..l_dense.COUNT INSERT INTO sw_table VALUES l_dense(i);INSERT INTO sw_table VALUES l_dense(i); END;END; $ELSE FORALL i IN INDICES OF sw_tab INSERT INTO sw_table VALUES sw_tab(i); $END END sw_insert; END sw_bulk_insert;
    30. 30. Paradigm Examples
    31. 31. Latent debugging code
    32. 32. CREATE OR REPLACE PACKAGE pkg_debug IS debug_flag CONSTANT BOOLEAN := FALSE; END pkg_debug; / CREATE OR REPLACE PROCEDURE sw_proc IS BEGIN $IF pkg_debug.debug_flag $THEN dbms_output.put_line ('Debug=T'); $ELSE dbms_output.put_line ('Debug=F'); $END END sw_proc; /
    33. 33. Assertions
    34. 34. “Assertions should be used to document logically impossible situations — Development tool Testing Aid In-line Documentation if the ‘impossible’ occurs, then something fundamental is clearly wrong. This is distinct from error handling.” Run-time Cost
    35. 35. Latent Assertions
    36. 36. “The removal of assertions from production code is almost always done automatically. It usually is done via conditional compilation.”
    37. 37. $IF $$asserting OR CC_assertion.asserting $THEN IF p_param != c_pi*r*r THEN raise_application_error(.. END IF; $END -- individual program unit -- entire application
    38. 38. Testing subprograms only in package body
    39. 39. CREATE PACKAGE universe IS PROCEDURE create_sun; PROCEDURE create_planets; -- CC test procedure PROCEDURE test_orbit; END universe; CREATE PACKAGE BODY universe IS -- Private PROCEDURE orbit IS .. END; -- Public PROCEDURE create_sun IS .. END; PROCEDURE create_planets IS .. END; -- Testers PROCEDURE test_orbit IS BEGIN $IF $$testing $THEN orbit; $ELSE RAISE program_error; $END END test_orbit; END universe;
    40. 40. CREATE PACKAGE universe IS PROCEDURE create_sun; PROCEDURE create_planets; -- CC test sequence PROCEDURE test_run; END universe; CREATE PACKAGE BODY universe IS -- Private PROCEDURE orbit IS .. END; -- Public PROCEDURE create_sun IS .. END; PROCEDURE create_planets IS .. END; -- Test sequence PROCEDURE test_run IS BEGIN $IF $$testing $THEN create_sun; create_planets; orbit; $ELSE RAISE program_error; $END END test_run; END universe;
    41. 41. Mock objects
    42. 42. FUNCTION get_emp(p_emp_id IN emp.emp_id%TYPE) RETURN t_emp IS l_emp t_emp; BEGIN $IF $$mock_emp $THEN l_emp.emp_name := 'Scott'; .. RETURN l_emp; $ELSE SELECT * FROM emp INTO l_emp WHERE emp_id = p_emp_id; RETURN l_emp; $END END get_emp;
    43. 43. Comparing competing implementations during prototyping
    44. 44. PROCEDURE xyz IS $IF $$alternative = 1 $THEN -- varray declaration $$ELSIF $$alternative = 2 $THEN -- nested table declaration $END BEGIN $IF $$alternative = 1 $THEN -- simple varray solution $$ELSIF $$alternative = 2 $THEN -- elegant nested table solution $END END xyz; PROCEDURE xyz ISPROCEDURE xyz IS $IF $$alternative = 1 $THEN$IF $$alternative = 1 $THEN -- varray declaration-- varray declaration $$ELSIF $$alternative = 2 $THEN$$ELSIF $$alternative = 2 $THEN -- nested table declaration-- nested table declaration $END$END BEGINBEGIN $IF $$alternative = 1 $THEN$IF $$alternative = 1 $THEN -- simple varray solution-- simple varray solution $$ELSIF $$alternative = 2 $THEN$$ELSIF $$alternative = 2 $THEN -- elegant nested table solution-- elegant nested table solution $END$END END xyz;END xyz; $IF $$alternative = 1 $THEN -- first verbose solution that came to mind $$ELSIF $$alternative = 2 $THEN -- some crazy idea you came up with at 3am you need to try out $END
    45. 45. Component Based Installation
    46. 46. PACKAGE BODY core IS PROCEDURE execute_component(p_choice IN VARCHAR2) IS BEGIN CASE p_choice -- Base is always installed. WHEN 'base' THEN base.main(); $IF CC_licence.cheap_installed $THEN WHEN 'cheap' THEN cheap.main(); $END ... $IF CC_licence.pricey_installed $THEN WHEN 'pricey' THEN pricey.main(); $END END CASE; EXCEPTION WHEN case_not_found THEN dbms_output.put_line('Component '||p_choice||' is not installed.'); END execute_component; END core;
    47. 47. Get It Right with the Error Directive
    48. 48. $IF $$PLSQL_OPTIMIZE_LEVEL != 2 $THEN $ERROR 'intensive_program must be compiled with maximum optimisation' $END $END
    49. 49. BEGIN ... /* * * Note to self: Must remember to finish this bit * */ ... END;
    50. 50. BEGIN ... -- Jacko: this doesn’t work, fix before moving to prod! ... END;
    51. 51. 1 CREATE PROCEDURE process_court_outcome IS 2 BEGIN 3 IF lr_victim.age > 18 THEN 4 send_to_prison(lr_victim); 5 ELSE 6 $ERROR 7 'Waiting for business to advise '|| 8 $$PLSQL_UNIT||' line: '||$$PLSQL_LINE 9 $END 10 END IF; 11 END process_court_outcome; 12 / Warning: Procedure created with compilation errors. SQL> sho err LINE/COL ERROR -------- ---------------------------------------- 6/6 PLS-00179: $ERROR: Waiting for business to advise PROCESS_COURT_OUTCOME line: 8
    52. 52. Post-processed Source Demo: cc2
    53. 53. Smaller, Faster Run-Time Code Is in Your Future
    54. 54. Good Practices
    55. 55. Inquiry directives have null values for normal behaviour $IF $$cc_flag = 'x' $THEN cc_code; $END
    56. 56. Choose restriction type carefully $IF $$debug_on OR module_y.cc_debug $THEN sw_debug('Error'); $END
    57. 57. but there’s always this...
    58. 58. SQL> define debug=/* begin &debug select 'conditionally' from dual; -- */ select 'always' from dual; end; /
    59. 59. SAGE Computing Services Customised Oracle Training Workshops and Consulting Questions and Answers? Presentations are available from our website: http: //www. sag e co m puting . co m . au e nq uirie s@ sag e co m puting . co m . au sco tt. we sle y@ sag e co m puting . co m . au http: //triang le -circle -sq uare . blo g spo t. co m
    1. A particular slide catching your eye?

      Clipping is a handy way to collect important slides you want to go back to later.

    ×